Dead betta from constipation?

[BCGirl]

I lost one of my bettas and am so sad. I'm hoping to figure out the cause so I do not have a repeat. I suspect she/he ate some of the snail algae wafer and got constipated but I could be wrong. She has never had any issues and lives in a 10G heated with two zebra snails. I first noticed 4 days ago that she was acting strange. She wasn't coming for food or moving as much as usual and looked slightly swollen. I figured it was maybe constipation so I didn't feed her and kept an eye. All water parameters came back safe/normal. She gradually got bigger. I tried to give her peas but she wouldn't eat them and kept getting bigger. She never did pine cone so I assume it wasn't dropsy but maybe it just didn't have time to get there. As she wasn't eating peas I moved her into a smaller cycled quarantine tank with epsom salt last night as a last ditch effort following 1tsp/5 gallon ratio. This morning she died. I've attached a pic and you can see where her swelling was as it is white although now that she is dead it is harder to see. Any insight is greatly appreciated. I love my fish and am so sad I couldn't save her. Her diet consisted of Hakari gold pellets, another brand of pellet, Hakari daphnia, fluval bug bites and the occasional blood worm or brine shrimp. She got a bit of food two times a day.

[Colu]

The fact that she died so quickly it's more then likely an internal bacterial infection